Results

***PWB116

2018 - 2023

Towards the determination of the level of dietary phosphorus and calcium in pullets and laying hens that will optimize body mineral status, maximize the performance, longevity, welfare and the industry sustainability

Objective

The overall objective of this research is to develop a mathematical model of the fate of dietary phosphorus and calcium in pullets and laying hens to establish dietary recommendations. Specifically, the researchers intend to:

Adapt a model that was developed in broilers for the flow of dietary phosphorus and calcium to that in pullets and laying hens;

Predict the effect of Ca particle size on Ca use and integrate particle size into the model; and Validate the model in an animal trial.

Background

Animal manure is a valuable fertilizer and may be used to reduce the use of mineral fertilizers and to improve soil structural stability and biodiversity. However, when slurry spreading exceeds the recycling capacity of the farmland and the surrounding natural environment, negative impacts on soil occurs, the air is fouled, and waterways undergo eutrophication, resulting in bad press for the livestock industry. As part of this research, a model of the fate of dietary calcium and phosphorus in the digestive tract, the soft tissues, the bone and the egg of pullets and laying hens will be developed. This will be done by modifying a model developed in broilers using data available in literature or coming from the research team implicated, especially new data of body composition of modern pullets and laying hens and regulations between intestine, bone and kidney during egg shell formation. This research model will be a multicriteria tool allowing to assess dietary recommendations depending on most important criteria, among them the egg cycle timing, the housing system, and the type of feeding.